Boosting Performance Through Creative Surgery

V12 From Two Toyota I6 Engines Update

It has been a while since we last wrote about the V12 engine build using two Toyota inline-six engines. Recently a relative of the builder posted new pictures and information. To start the V12 is being built from two 1JZ engines. The engine uses a custom crank from Scat Crankshafts with SBC main bearings, Honda rod bearings, Honda H-beam rods. The heads have been reversed so the exhaust ports are facing inward. The oil pan has been custom made from aluminum and setup for a dry sump system. The goal will be 800 horsepower which this engine should be able to do in its sleep.

Since the last article I have been researching the history of V12 builds using two inline-six engines and found this is more common than I thought. Several engine builders and companies have built V12 engines using two inline-six engines. Toyota’s 1GZ-FE V12 shares similarities with 1JZ engines. Below is a quote from Lextreme article on the 1GZ-FE.

The 1GZ-FE in many ways is two inline six cylinder engines sharing a common crank. This is evidenced by there being dedicated left and right cylinder bank inlet manifolds, throttle bodies and EFI systems – to the extent that there are separate ECUs for each bank, with the engine capable of running as a six cylinder engine (with a 6 cylinder air compressor along for the ride) should one bank suffer a significant failure.

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10 Comments

The author is mistaken, Just because this engine is made from two 1JZ engines, and because some dude who is writing a blog and, knows little about the Toyota engines and their history, imagines that the 1GZ-FE V12 is made from two 1JZ engines doesn’t make it so. That’s like saying that Toyota’s hemi V8 – Japans first domestically-manufactured V8 that was used in the Crown 8 and then in the Century as the V, 3V, 4V and 5V models was made from two 2TC 4-cylinder engines when the 2TC was derived FROM the 3V – not the other way around. It has two ECU’s and two separate intake systems so the author assumes it must be cobbled together; when that was a design decision opting for redundancy. If one ECU fails, there is another one there and the engine is capable of running on one bank of cylinders so the VIP being chauffeured around in the Century isn’t ever stranded and inconvenienced. Are there parts that can interchange between the 1JZ sixes and the 1GZ twelves? You betcha, but many of Toyotas engines have common components – I should know, I’m a former Toyota mechanic. This is a one-off. The angle between cylinder banks is hugely different. The exhaust is on top versus on the bottom. the cylinders are obviously sawn off two 1JZ blocks. The 1GZ-FE has a one-piece cast short block. I’ll grant the builder kudos for imagination and some beautiful work but stop imagining this is where the 1GZ-FE idea comes from. To figure where the 1GZ-FE idea came from, it makes more sense just to imagine Toyota deciding to lengthen the 5V engine by one cylinder per cylinder bank.

Thank you for clarifying. Using the 1GZ-FE as an example might have been a poor decision, considering the points you make, but my attempt (which was poorly written) was to show that V12 engines have a history of being made from inline-six engines. When researching I came across the article (Lextreme.com) showing the similarities between the 1GZ-FE and the 1JZ and went further with the assumption than did Lextreme. Lextreme never said that it “was made from two 1JZ engines”, only I made the ill-advised assumption. I will correct this article to be more accurate by saying they only share certain similarities.

Hi, No harm, no foul. It’s still some very nice work though. I’m sure it will turn a lot of power. Back in the late 60’s Toyota used to distribute a company magazine to the mechanics that worked in the dealerships. I remember an article about a GT type racer called the Toyota 7. That engine was a 5 liter V8 that made just over 800 bhp and turned something like 525 pf of torque. During testing the engine destroyed two different racing transaxles so Toyota had to come up with their own design to handle the torque. I don’t think the car ever actually made it into competition because a driver died in an accident, or something like that, and Toyota pulled out of factory sponsored racing altogether. It was a lot of years before they returned to the racing circuit. It’s going to be interesting to see what this car will do.

What would have been uber-cool to see though would have been a V16 made from two 1GZ-FE’s in line. The blocks shaved and fitted together where they meet; so they could use 1 custom crank, 4 modified heads, four custom-made cams instead of 8, one custom-made intake system and one custom-made exhaust system, one dry sump system and maybe quad turbo-charged. What an animal that would be!